Hydrochloric Acid → Bis(3-amino-4-fluorophenyl)methanone

Participants

Reaction Conditions

Reaction Steps

To a glass reaction vessel equipped with a stirrer, reflux condenser and a thermometer, 124 g (0.4 mole) of 3,3'-dinitro-4,4'-difluorobenzophenone, 1100 ml of a 80% aqueous ethanol solution and 280 g (5.0 mole) of iron powder were charged and the internal temperature was raised to 75 ° C. Successively, a solution containing 10.5 g of 36% hydrochloric acid in 124 ml of 80 % ethanol was added dropwise and the reaction was further continued for 3 hours with stirring. After finishing the reaction, the reaction mixture was filtered at the same temperature and the filtrate was poured into 2 l of water. The precipitated crystal was filtered, washed with water and dried to obtain 90.5 g of crude crystal of 3,3'-diamino-4,4'-difluorobenzophenone. The crude crystals were mixed with 180 ml of water, 36% hydrochloric acid and activated carbon, and dissolved by heating. The solution was hot filtered. To the filtrate, 18 g of sodium chloride was added and dissolved. The solution thus obtained was gradually cooled to precipitate 3,3'-diamino-4,4'-difluorobenzophenone hydrochloride. The hydrochloride was filtered and neutralized in water with a 28% aqueous ammonia solution to obtain 82.3 g (83.0% yield) of 3,3'-diamino-4,4'-difluorobenzophenone. The purified product had purity of 99.1% by high performance liquid chromatography and a melting point of 130.8+-131.6° C.

Provenance & Evidence